VEC TEC, Inc. will develop a diagnostic test system consisting of a frozen panel of human vascular endothelial cells. The frozen panel will be used clinically to identify detrimental sensitization in patients awaiting a solid organ allograft. During Phase I, the cryopreservation techniques necessary for optimized viability of the endothelial cells will be developed. Issues pertaining to proper packaging of the test cells, as well as identifying appropriate lots of accompanying reagents will also be addressed during Phase I. A retrospective field trial, in collaboration with Brigham and Women's Hospital, will be initiated during Phase I to assess the potential clinical relevance of implementing this diagnostic test system. The proposed test system represents a novel approach to assessing histocompatibility and will serve as a supplemental assay the lymphocyte as the cell target in histocompatibility assays. However, rejection can be mediated by antibodies directed against antigens specific for vascular endothelial cells. The development of a frozen vascular endothelial cell panel may identify those patients at risk for early allograft rejection.